In the picture gallery the arrow to drive the picture from right to left  are not working only the automatic changing mode work.

When I am looking at the web site from any browser I have in stay of the arrow I have  a black  hand logo or a black square logo with a arrow pointing in 4 corners .

Why? How can I make the image gallery work?

I try to resize the image , the cell none of it seam to work\Please help